Travellers faced continuing delays today as ash from the Iceland volcano continued to disrupt airline schedules.

Most people heading for European destinations had relatively minor problems despite a few cancellations. But severe disruption continued to hit transatlantic flights as aircraft were forced into long detours around the ash cloud, adding hours to flight times.

All European airports were open this morning after ash concentrations over the continent dispersed, but ash may head back towards Portugal and Spain this afternoon, causing more problems.

Airlines were reducing flights to some destinations but providing bigger aircraft to carry more passengers as they tried to keep to their timetables after another weekend of travel disruption.

The Eurocontrol air traffic body said it expected 28,500 flights in European airspace today, about 500 below average. Traffic levels yesterday were 1,500 flights down as the plume closed airports from Scotland to northern Italy.

Flights to and from the US, Canada and the Caribbean were often several hours late, while Ryanair cancelled 18 flights today, including some between the UK and Faro, in Portugal.

EasyJet, which had to cancel some flights yesterday, said it was operating a near-normal service today with "only a very small number of cancellations".

British Airways said it was trying to keep passengers informed "but it is a challenge when the cloud keeps moving around".

Airports and airlines continued to urge passengers to check the latest information before travelling to their airport. The controlling body for UK airspace, Nats, said: "The high density area of the volcanic ash cloud is now lying to the north-west of the UK and, as a result, there are currently no restrictions within UK airspace."

The Civil Aviation Authority, which agrees no-fly zones based on Met Office data, said current forecasts indicated skies over Britain should remain clear for the next 18-24 hours.

A Met Office spokeswoman said: "We're all at the mercy of the volcano and there is just no way of knowing how long it will continue to erupt. We would normally be getting south-westerly winds at this time of year and it's pretty unusual to have northerly winds dominating the weather. It's very much a day-to-day situation at the moment. The volcano died down a bit for a spell and has now got more active."